Validation of the Women's Health Initiative Insomnia Rating Scale in a multicenter controlled clinical trial.

Objective: The objective of this study was to evaluate the construct validity of the five-item Women's Health Initiative Insomnia Rating Scale (WHIIRS) by comparing women taking hormone therapy (HT) versus those taking a placebo and by comparing women known to differ in vasomotor symptoms.

Methods: The WHIIRS was included in two phase III randomized trials intended to evaluate the efficacy of a combination estradiol plus and norethindrone acetate transdermal delivery system in reducing vasomotor symptoms. In all, 850 healthy postmenopausal women participated in these studies.